In the field of gas turbine technology, a great deal of effort has been, and continues to be, directed toward improving thermodynamic efficiency by operating gas turbine engines at increasing temperatures. These temperatures may exceed the temperatures that some materials within the turbine engine structure can normally tolerate. As such, cooling air may be provided to various turbine engine components using cooling air extracted from other parts of the engine. For example, in some gas turbine engines, cooling air is extracted from a plenum at the discharge of the compressor, and is then directed to certain portions of the turbine.
For some gas turbine engines, the air that is extracted from the engine for turbine cooling may be at temperatures that require the air to be cooled before being directed to the turbine. In some turbofan gas turbine propulsion engines, a portion of the fan air flowing in the bypass duct may be continuously redirected and used to cool the extracted turbine cooling air in a heat exchanger. Conventional plate-fin heat exchange architectures, however, are susceptible to thermo-mechanical fatigue (TMF), especially at braze connections, as they do not allow adequate thermal growth and stress compliance during transient and steady state operations, thereby reducing their service life and/or necessitating costly repairs. For example, components of conventional heat exchangers may be rigidly coupled to each other, restricting relative motion and inducing stresses in the heat exchanger.
Hence, there is a need for heat exchange systems with compliant components for improved TMF life, while maintaining heat exchange performance efficiency. The present disclosure addresses at least this need.